Technical Field
The present disclosure relates to a touch sensitive device and a display device including the same, including a touch sensitive device with improved vibration level and light transmittance and a display device including the same.
Description of the Related Art
There has been an increased interest recently in touch type display devices , in which users can input information by touching the display device, because users want to use various display devices, such as a liquid crystal display device and an organic light emitting display device, easily. Accordingly, research into utilizing haptic devices has increased to provide direct and various touch feedbacks to the users. Conventional haptic devices are attached to the back of the display panel, and thus, it is difficult to provide an immediate and accurate feedback to a user's touch. Accordingly, research is being actively conducted to provide sensitive, varied and direct feedbacks to a user's touch by positioning the haptic device on an upper surface of the display panel.
Conventionally, a vibratory motor, such as an eccentric rotating mass (ERM) or a linear resonant actuator (LRA), has been used as a haptic device in a display device. The vibratory motor is designed so that the whole display device vibrates, and thus, such a massive vibratory motor is required in such a device to increase vibration intensity. The vibratory motor also has other disadvantages, in that it is difficult to modulate the frequency required to control the degree of vibration, thereby significantly increasing the response time.
In order to solve the problems described above, a shape memory alloy (SMA) and an electroactive ceramics (EAC) have been developed as suitable materials for haptic devices. However, a shape memory alloy (SMA) has a long response time, a short lifespan and is opaque, and electroactive ceramics (EAC) have low durability against an external impact, and are thus, fragile. Further, like the eccentric rotating mass and the linear resonant actuator, an electroactive ceramic actuator is opaque and it is difficult to manufactured a slim device.